Traveling crane



P. D. NIELSEN TRAVELING CRANE April 9, 1940.

Filed llay 17', 1959 Patented Apr. 9, 1940 PATENT OFFICE TRAVELING CRANE Peer D. Nielsen, Lorain, Ohio, assignor to National Tube Company, a corporation of New Jersey Application May 17, 1939, Serial No. 274,270

1 Claim.

This invention relates to overhead traveling cranes carrying two electrically powered trolleys. such as a hook trolley and a bucket trolley. One of the objects is to provide for the individual operation of these trolleys without necessitating the crane operator leaving his cab and throwing switches on the trolleys.

A specific example of the invention is illustrated by the accompanying drawing, in which:

Figure l is a side view of the bridge of an overhead traveling crane incorporating the invention; and,

Figure 2 is a wiring diagram illustrating the principles of the invention.

15 More specifically, the drawing illustrates the tracks I over which the crane bridge 2 transversely travels, this bridge consisting of spaced girders carrying trolley tracks 3 forming a trackway for a bucket trolley 4 and a hook trolley 5,

20 respectively, powered to travel over the trolley trackway, by motors 6 and 1.

One of the girders oi the bridge 2 longitudinally carries electric conductor bars 8, each of the trolleys 4 and 5 carrying staffs 8 and I0, re-

25 spectively, mounting electric collector shoes H and i2 which slide over the bars 8. The shoes II and I2, respectively, connect with the motors 8 and I, whereby energization of the bars 8 energizes the trolley motors. A crane operators 30 cab I3 is suspended from one end of the bridge 2, and suitable electrical controls are centralized in this cab for the convenience of the operator, these controls including a control system for electrically energizing the bars 8 to power the motors 35 6 and I.

It is undesirable to operate both of the trolleys at once, and it is the prior art practice to provide manually operated switches on each of the trolleys i'or disconnecting their motors from their collector shoes. The use of these switches enables either one or the other of the trolleys to be operated, but their operation necessitates the crane operator leaving his cab l8 and climb- 45 mg on the crane bridge walkway. This exposes him to danger and is a generally unsatisfactory procedure.

According to the present invention, opposite end portions 8 and 8 of the bars 8' are segre- 50 gated from the portion 8 therebetween. The

portions 8' and 8 are as short as they can possibly be made and still enable the adjacent trolley to be run to a position where its collector shoes I slide onto the segregated portions. The

as segregation is accomplished by interposing insulators it between the segregated and main portions of the bars 8.

Furthermore, the trolley control system is provided with switches operable from the cab l8 for selectively energizing either of the end por- 5 tions 8" or 8 and the main portion 8 without simultaneously energizing both of the end portions 8 and 8 With this arrangement, the operator can run the trolley that he does not desire to use to the adjacent end portion of its 10 trackway, this bringing its collector shoes onto the segregated end portion of the bars 8. Then, by deenergizing this end portion and energizing the other end portion and the central portion 8 of the bars 8, control of the other trolley is possible without energizing the motor of the trolley run to the end of its trackway.

A suitable circuit for accomplishing the above is illustrated by Figure 2 as consisting of a fourpole, double-throw safety switch l5 adapted to connect power lines I6, which are connected to the portion 8 of the conductor bars 8, to either of the end portions 8 or ii by way of lines I1 and I8, respectively. The switch i5 is of the type having interlocked switching elements which positively prevent energization of the lines I! and I8 at the same time, this switch l5 being located in the cab l3 for the convenience of the crane operator.

The reason there are four of the conductor bars 8 is because two of them directly energize the armatures 6 and I of the motors 6 and I, while the other two energize the series fields 6 and l of these motors, whereby proper connections through the control equipment located the cab i3, permit reversing operation or the trolley motors in the conventional manner.

I claim:.

A crane including a transversely traveling bridge, a trolley trackway longitudinally carried by said bridge, at least two trolleys traveling said trackway, electric motors carried by said trolleys for powering the same to travel over said trackway, electric conductor bars extending longitudinally of said bridge, electric collecting elements carried by said trolleys and slidingly contacting said bars, said elements electrically connecting with said motors so that electric energization of said bars powers said motors, a crane operators cab carried by said bridge and electric control equipment centralized in said cab for the convenience of the crane operator and including a control system for electrically energizing said bars to power said motors, said bars having opposite end portions electrically in- 5 said trolleys without simultaneously enerflzin: the other, y positioning the other trolley so its collector element slides to one or the other of the insulated end portions of said burs.

PEER D. NIELSEN. 

